Abstract
Aging is associated with structural and functional brain changes which may impact the regulation of motivated behaviors, including both action and inhibition of action. As behavioral regulation is often exercised in response to reward, it remains unclear how aging may influence reward-directed action and inhibition of action differently. Here we addressed this issue with the functional magnetic resonance imaging data of 72 participants (aged 21–74) performing a reward go/no-go (GNG) task with approximately 2/3 go and 1/3 no-go trials. The go and no-go success trials were rewarded with a dollar or a nickel, and the incorrect responses were penalized. An additional block of the GNG task without reward/punishment served as the control to account for age-related slowing in processing speed. The results showed a prolonged response time (RT) in rewarded (vs. control) go trials with increasing age. Whole-brain multiple regressions of rewarded (vs. control) go trials against age and RT both revealed an age-related reduced activity of the anterior insula, middle frontal gyrus, and rostral anterior cingulate cortex. Furthermore, activity from these regions mediated the relationship between age and go performance. During rewarded (vs. control) no-go trials, age was associated with increased accuracy rate but decreased activation in the medial superior frontal and postcentral gyri. As these regions also exhibited age-related activity reduction during rewarded go, the finding suggests aging effects on common brain substrates that regulate both action and action inhibition. Taken together, age shows a broad negative modulation on neural activations but differential effects on performance during rewarded action and inhibition of action.
Highlights
Aging is associated with changes in brain structures and functions including those underlying goal-directed behaviors (Marschner et al, 2005)
Employing a GNG task, we examined the effects of age on behavioral performance and neural processes during rewarded action and inhibition of action, controlling for individual differences in gender and reward and punishment sensitivities
Age was associated with prolonged response time (RT) and a reduction of activity in the anterior insula, middle frontal gyri (MFG), rACC, and dACC during rewarded action
Summary
Aging is associated with changes in brain structures and functions including those underlying goal-directed behaviors (Marschner et al, 2005). In the monetary incentive delay task, age was negatively correlated with neural activations to anticipated large vs small rewards in regions implicated in reward processing, including the orbitofrontal cortex and ventral striatum (Dhingra et al, 2019) These findings support previous reports of reduced dopaminergic signaling and reward sensitivity in aging (Kish et al, 1995; Volkow et al, 1996; Kumakura et al, 2010). Older adults showed reduced sensitivity to winning a large vs small reward, they were more sensitive to the loss of a small vs large reward as compared to younger adults (Dhingra et al, 2019) These age-related changes in reward and risk/loss sensitivity likely influence motivated action and inhibition of action, respectively. We used mediation models to investigate the inter-relationships between age, behavioral performance, and brain activations while controlling for processing speed and trait sensitivities
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call